The invention relates to thermo-mechanical processing of tool steel, methods of forming tools using thermo-mechanically processed tool steel, and tools used in metal-forming and metal-cutting applications.
Among the various grades of commercially available carbon and alloy steels, tool steel grades are commonly used in applications wherein the tools undergo severe stresses, impact, and/or wear. Tool steels are generally characterized by a distinctive hardness, resistance to abrasion, an ability to hold a cutting edge, and a resistance to deformation at elevated temperatures. Consequently, tool steel finds widespread use in metal-forming and metal-cutting applications, inspection equipment and gages, and wear/impact components in machine tools.
Various types of tools are used in metal-forming and metal-cutting applications such as machining, piercing, coining, drawing, powder compaction, metal engraving, pin stamping, and the like. In particular, punches and dies represent types of metal-forming tools used to pierce, perforate, and shape metallic and non-metallic workpieces. Cutting tools and inserts represent types of metal-cutting tools used in machining applications to shape metallic and non-metallic workpieces. Plug gages, thread gages, pipe gages, ring gages, and setting disks represent types of tools used in inspection applications. Machine slides and gibs represent types of wear and impact components used in machine tools.
Punches and dies are subjected to severe and repeated loading during their operational life. In particular, punches tend to fail during use from catastrophic breakage induced by the significant stresses experienced during their use. The demands on metal-forming tools become more severe with the introduction of workpieces constructed from steels having higher strength to weight ratios, such as ultra-high strength steels (UHSS), advanced high-strength steels (AHSS), transformation induced plasticity (TRIP) steels, twinning induced plasticity (TWIP) steels, nano steels, and martensitic (MART) steels. For example, the automobile industry is migrating toward the more frequent use of these types of high-strength, low-weight steels for vehicle body structures.
What is needed, therefore, are methods of thermo-mechanically processing tool steels to improve the mechanical properties thereof and tools formed by thermo-mechanical processing that have improved mechanical properties.